public Task<IRestResponse> ProcessCustomRequest(IRestRequest request, string url, CancellationToken cancellationToken)
      {
          var client = new RestClient(url);
          
          client.UserAgent = "Mozilla/5.0 (compatible; MSIE 10.0; Windows Phone 8.0; Trident/6.0; IEMobile/10.0; ARM; Touch; NOKIA; Lumia 920)";
 
          return client.ExecuteRequestAsync(request, cancellationToken);
      }
        public Task<IRestResponse> ProcessRequest(IRestRequest request, bool secureConnection, CancellationToken cancellationToken, string url = "wp8-ebook.litres.ru")
        {
            //url = "whub.litres.ru"; // test domen
			var client = new RestClient( string.Format( "http{0}://{1}/pages", secureConnection ? "s" : "", url ) );
#if DEBUG
            RequestToString(request, client);
#endif
			return client.ExecuteRequestAsync( request, cancellationToken );
		}
		public Task<IRestResponse> ProcessStaticRequest( IRestRequest request, CancellationToken cancellationToken )
		{
			var client = new RestClient( "http://wp8-ebook.litres.ru/static" );
            
			return client.ExecuteRequestAsync( request, cancellationToken );
		}